Spring kafka consumer not receiving messages 

Spring kafka consumer not receiving messages. Sometimes after a while the listener restarts and sometimes doesn't. You use KafkaEmbedded and its properties to configure ProducerConfig, but at the same time I don't see how you configure ConsumerConfig. Jun 9, 2021 · I was trying to see if a service is invoked when the consumer receives a message from kafka topic but the test is not passing and the consumer is not even receiving the message. This article covers the basics of Kafka, the Spring Kafka library, and a simple producer and consumer example. Configure the KafkaConsumer node by setting the following properties: On the Basic tab, set the following properties: In the Topic name property, specify the name of the Kafka May 11, 2018 · I am building a Kafka Consumer application that consumes messages from a Kafka Topic and performs a database update task. AckMode. Jun 9, 2018 · 3. As mentioned on the git issue, the only workaround is to fix this via the kafka consumer CLI tool. On the inbound side, all Kafka Header instances are mapped to MessageHeaders . Starting with version 2. . Assign or subscribe to a topic 3. But sometime errors are occurred while message handling. RELEASE and int-kafka:message-driven-channel-adapter to consume messages from the remote kafka topic. I put more partitions than actual instances and it does not work. That is an application-level function. poll(Duration. @KafkaListener(topics = "test", containerFactory = "kafkaListenerContainerFactory") logger. Apr 8, 2017 · Verify that the producer is actually writing to the topic using the following command /usr/bin/kafka-avro-console-consumer --new-consumer --bootstrap-server localhost:9092 --topic KumarTopic --from-beginning. The first step is to check the consumer’s subscription. Apr 27, 2019 · I'm trying to integrate kafka with my Spring boot (v2. When the Apr 15, 2022 · return HttpResponse(200) and consumer. For example - in the kafka console producer, I would type "one" -> Enter ->"two" -> Enter -> "three" -> Enter. To implement a retry logic for message processing in Kafka, we need to select an AckMode. . but it didn't get the message as well, probably the message is not in the kafka. Essentially you should use the same properties from the EmbeddedKafka. If you want to test with a real Kafka broker, see the test-embedded-kafka sample app. This is the first place where our message originates. Actually each instance receives message only if the instance have different group id. Kafka maintains order within a single partition by assigning a unique offset to each message. Finally, polling the same consumer again for messages now reads all the messages from the beginning of the partition: ConsumerRecords<String, String> records = consumer. Kafka Producer Configuration. conf. To do this, I found two ways. 2) What I need to do is, to listen that topic and get this message with the key, and create a new key by using that Key. Also to reduce complexity, I am changing code to test with StringDesilizer instead of custom JSON deserilizer. but if I pass any text it throws exception. 12 and I'd like to consume messages from a topic after a certain period of time after the message sending. And if I use separate @kafkaListener for each topic then 2 MessageListenerContainer will be created. e. Similarly, ConsumerFactory instantiates Kafka consumers. consumer. The first time u run the consumer its registering with the group coordinator. 1) First microservice sends message to Kafka with a key which is instance of MyKey object. This property lists the Kafka broker addresses that your consumer will connect to: spring. sh --bootstrap-server localhost Jan 8, 2024 · Let’s look into these configs in detail to send a large message of 20MB. My test: Mar 19, 2023 · To test the consumer, you can produce messages to the “my-topic” Kafka topic. I do my code as bellow and get this problem. listener. Aug 13, 2020 · Multi-Threaded Message Consumption with the Apache Kafka Consumer. Net core to interact with Kafka. Kafka nuget package for both producer and consumer. 6. properties: Every single client runs all this code. The account-service can generate and consume its own events but they aren’t making it Sep 13, 2016 · I'm having a strange outcomes: when I send messages using kafka-console-producer. The message collector is simply fetching it from the channel. } On a topic we will receive near about 200K messages per second. edited Jun 9, 2018 at 18:12. So each thread is deciated to a partition. Use the following command to send a test message: . Jun 30, 2022 · Nevertheless, if you do not want to receive old messages, that has not been ack before, you need to move offset for you consumer group. In order to find out till what offset the consumer has consumed the messages use this kafka-consumer-offset-checker. commit. I have a project with 2 @KafkaListener and after some time one of the 2 listener stop to receive messages. send("topic", "Hello World!"); To consume the messages, a @KafkaListener is used: System. Instead, they are registered with an infrastructure bean of type KafkaListenerEndpointRegistry . If it is, you'll probably need to focus on your consumer code. bootstrap-servers=localhost:9092,localhost:9094. bootstrap-servers. If you have set a linger. KafkaConsumer. 7: Use this interface for processing all ConsumerRecord instances received from the Kafka consumer poll() operation when using auto-commit or one of the container-managed commit methods. If there is no output means that the messages are probably not there or you have some difficulty connecting to it. The framework cannot know whether such a message has been processed or not. Sep 14, 2021 · public void receivedMessage(ConsumerRecord<String, String> cr, @Payload String message){. loads(message. Mar 21, 2022 · No Axon server. Apr 28, 2022 · Kafaka Subscriber not receiving the messages. It also works, when I bind consumer in command line - i see messages sent by java-code-producer. This first part of the reference documentation is a high-level overview of Spring for Apache Kafka and the underlying concepts and some code snippets that can help you get up and running as quickly as possible. assignment () method returns the set of partitions currently assigned to the consumer. This sets the strategy for creating Kafka Producer instances. cloud. 8, you can now set the container property asyncAcks, which allows the Access to the Consumer object is provided. Also, when you change your group. ' in producer properties acks = 1. Any way I can call a mongoDB from Kafka Consumer? full log stack: org. If broker does not receive heartbeats from the consumer, it considers the consumer dead and reassigns its partitions. enable-auto-commit=false There will be no data to consume at the end of the topic until the consumer is running while a producer sends data. Jun 19, 2018 · 0. value) result = deserialized_data['msg'] all images are running and when I try send message from producer, consumer doesn't receive it. May 19, 2019 · We are using spring-integration-kafka version 3. The messages are produced in a large batch once every day - so the Topic has about 1 million messages loaded in 10 minutes. You’ll need to connect to Kafka, and that’s where bootstrap-servers come in. I checked it with the kafka-console-consumer, where a new message is each and every time I run the test generated and appears on the console. If I run it through python, it hangs, which I suspect to be caused by incorrect consumer configs. Sep 14, 2017 · 0. And I have a consumer that must consume all type of message. lang. After that, we’ll test our implementation using the Producer API and Testcontainers. I have restarted each of the faulty consumers, but still no success. info("Message received from topic {} ", cr. Hence, the property “max. 1. First, create a new Consumer class with a method consume and an annotation with the topic that you’d like to listen to, as well as a groupId. Jan 8, 2024 · 4. Jun 8, 2020 · SUCCESS_LOG was printed when producing the message but consumers did not receive the message (there are 2 consumers with different group id's). Well, it looks like there is already a bug reported with spring-cloud-stream-binder-kafka stating the resetOffset property has no effect. 9, you don't use Zookeeper for consumption or production. Events generated in the account-service should also be consumed in the user-service. sh --bootstrap-server :9093 --topic test --from-beginning. bindings. See full list on codeflood. If you give correct broker parameters you will be able to consume messages. interval. Jun 8, 2021 · You can use Apache official Kafka client to create a consumer . Buy on Amazon. Seems that functionality should be used to reread messages in case of consumer failure, not when a component that uses the message fails. $ . I have tried running a another test consumer with a different group id. I am able to produce the message to Kafka. Ones I received message will send to another method for processing which filtered the messages based on certain criteria and Jul 5, 2019 · There could be some consumer configuration problem. However, when we scale up and use multiple partitions, maintaining a global order becomes complex. With the last two methods, each record is retrieved individually and the results assembled into a ConsumerRecords object. Sep 16, 2016 · Thanks. This is not the case when I'm testing the consumer with few hundred message. Listener class. Have checked the obvious parameters, including hostname and port of the bootstrap servers (which Aug 10, 2023 · Using @InputChannelAdaptor , I am polling messages from topic but not receiving any messages if I post json from commandline. In situations where the work can be divided into smaller units, which Jul 22, 2020 · Learn how to use Spring Kafka to send and receive messages from Kafka in your Spring Boot application. 2. KafkaTemplate This is because you are using the TestBinder in your test, not the real Kafka broker and kafka binder. SyncProducer: Connected to xx. So, if consumer dies, its partitions will be assigned to another consumer from the group and uncommitted messages will be sent to the newly Apr 5, 2018 · not working. You might get some clues looking at the logs (client and server). private final Logger logger = LoggerFactory. This will give you a Spring Boot project configured with a TypeScript-Lit front end. Hence, on the consumer always requested messages with the offset as latest. IllegalArgumentException' exception. And what I want to do in the listener is to create a new extended key as: Nov 2, 2021 · Use this interface for processing all ConsumerRecord instances received from the Kafka consumer poll() operation when using one of the manual commit methods. Then we need a KafkaTemplate, which wraps a Producer instance and provides convenience methods for sending messages to Kafka topics. ofSeconds( 10 )); May 31, 2022 · spring. That's it! You now have a working Spring Boot Kafka consumer. Nov 8, 2022 · i have an app that i want to open in multiple instances and i need each instance to receive the message. So, if a consumer isn't working the way you expect, look at the producer application first. sh —bootstrap-server X. bat --group group-1 --topic Apr 3, 2018 · consumer config: Producer & Consumer: Spring controller: This is my console output, as you see It sends a message but method doesn't receive anything. What’s new? Quick Tour. Now I doubt whether I use manual offset management for its intended purpose. Reading data from Kafka is a bit different than reading data from other messaging systems, and there are few unique concepts and ideas involved. After below configuration both Kafka and spring boot is working but API call to Kafka will hang for a while and there won't be any messages in Kafka topic When trying to implement a Unit-test in a spring-boot application, I can't retrieve a ConsumerRecord, though a custom Serializer using an own POJO is working. clients. xml: Then we’ll need two more dependencies specifically for our tests. 5 days ago · 1. consumer = KafkaConsumer('msg_topic', bootstrap_servers=['kafka:9092']) for message in consumer: deserialized_data = pickle. I have checked that my consumer code is running without any errors, and I have assigned it to the correct topic and partition. Learning Kafka and I want to know if there is any way to consume messages which have been queued/unconsumed when a API is down. Use the first method if the consumer’s Deserializer or the template’s MessageConverter can convert the payload without any additional information, either via configuration or type metadata in the reply message. MANUAL_IMMEDIATE, the acknowledgments must be acknowledged in order, because Kafka does not maintain state for each record, only a committed offset for each group/partition. --topic orders \. For a ConsumerFactory, you need to provide the property files or configurations that your consumer will use. If you wish to block the sending thread to await the result, you can invoke the future’s get() method; using the method with a timeout is recommended. Check the consumer’s subscription. We have created a Spring Boot application with a Spring-Kafka dependency, but are unable to read the messages within the new project. I have multiple producers that can send multiple type of event to one kafka topic. The app works as consumer/producer at the same time. Each line represents one record and to send it you’ll hit the enter key. auto. On the outbound side, by default, all MessageHeaders are mapped, except id, timestamp, and the headers that map to ConsumerRecord properties. This bean is automatically declared by the framework and manages the containers' lifecycles; it will auto-start any Sep 13, 2022 · Begin by creating a new Hilla project. Note: my JmsListener does reconnect on its own in the event of a caught exception with the MQ connection. As you can see, you need to know the partition and offset of the record(s) you need to retrieve; a new Consumer is created (and closed) for each operation. As of Kafka 0. topic property, which we injected using the @Value annotation in the configuration class. You need to wire up a listener container, using this constructor and provide it to the adapter using the listener Aug 21, 2016 · 6. MANUAL or AckMode. xx. and I get the below info in my logs printed:: 13/08/30 18:00:58 INFO producer. Aside from the Manually Committing Offsets. The MQ channel is set to a 5 sec heartbeat interval, but not sure how to configure this or the keep-alive in our Spring Boot app. Sep 21, 2022 · To produce the message, just invoke method "send (K, V) from KafkaTemplate": kafkaTemplate. The listener containers created for @KafkaListener annotations are not beans in the application context. It does not apply if the container is configured to listen to a topic pattern (regex). $ bin/kafka-console-consumer. Aug 12, 2017 · but when I use my local consumer script it is not working: bin/kafka-console-consumer. I am writing sample applications in . Jan 6, 2020 · 2. JsonNode data = new ObjectMapper(). TIME: In this manual mode, the consumer sends an acknowledgment after a certain amount of time has passed. Jan 8, 2024 · 2. 9. There are other ways you can check messages were sent to Kafka - by checking that the offsets of the topic partitions have changed using GetOffsetShell. I want to continue to receive the following messages as usual and at the same time be able not to lose that message and receive it, for example, the next time the service is restarted with the consumer Apr 15, 2015 · Whatever done on producer side, still the best way we believe to deliver exactly once from kafka is to handle it on consumer side: Produce msg with a uuid as the Kafka message Key into topic T1; consumer side read the msg from T1, write it on hbase with uuid as rowkey ; read back from hbase with the same rowkey and write to another topic T2 Oct 19, 2017 · 1. Offset is basically pointer at last successfully read item, so when consumer is stopped, it remains here until consumer starts reading again - that is the reason why "old" messages are read. From inside the second terminal on the broker container, run the following command to start a console producer: kafka-console-producer \. This command will list all of the topics that the consumer is subscribed to. May 11, 2024 · The KafkaConsumer. 6 Jan 8, 2024 · 2. As a variant, the KafkaMessageListenerContainer can accept org. --bootstrap-server broker:9092. Command to send message to Topic: May 2, 2023 · I basically want a simple way to fetch data from a topic in a synchronous way but every time I try to use my KafkaTemplate to receive messages. @Qualifier("demoConsumerProcessor") public Consumer<KStream<String, String>> demoConsumerProcessor(){. Although I am not sure why I am not receiving any messages from the producer. What to do when there is no initial offset in Kafka or if the current offset does not exist any more on the server (e. def run(): Jun 15, 2022 · 1. Overview. I have downloaded Kafka and Zookeeper official docker images to my machine. Normally, when using AckMode. Partition array argument to specify topics and their partitions pair. Problem: Kafka messages are not being received/consumed across services. offset. 0. info("event={}", event); But in this case all messages come Dec 17, 2021 · To start with, check and confirm all the partitions are receiving messages from producers; Once it is confirmed, check the partition assignment strategy during the consumer start and confirm the consumer client is assigned with all partitions of the topic. kafka. The Topic has 8 partitions. In certain scenarios, such as rebalancing, a message that has already been processed may be redelivered. You can repeat this test both on the Kafka machine and from outside. /kafka-console-consumer. 11-0. id to something else and test. log. I have also set the auto_offset_reset to 'earliest' to make sure that it starts from the beginning of the topic. Logs. We’ll be focusing on setting up a KafkaConsumer without relying on Spring Boot modules. EDIT Introduction. stream. ack-mode=MANUAL_IMMEDIATE spring. Consumer configuration values are as below. Add a KafkaListener annotation to a plain old Java object in your Spring application so that it can consume messages asynchronously from Apache Kafka topics on Confluent Cloud. Receiving Messages. request. RELEASE) app using spring-kafka. The first approach is as follows, and I believe it's the more conventional approach: private final TestProcessor testProcessor; private final TaskScheduler scheduler = new Sep 28, 2016 · Looks like the data is not getting committed for some reason. I got the producer to work just fine, I can see the messages being sent to the topic through a console consumer. When you used kafka-console-conumser. springframework. Although the Serializer and Deserializer API is quite simple and flexible from the low-level Kafka Consumer and Producer perspective, you might need more flexibility at the Spring Messaging level, when using either @KafkaListener or Spring Integration’s Apache Kafka Support . Use the Vaadin CLI to initialize the project: npx @vaadin/cli init --hilla --empty hilla-kafka. 3. 11. Producing Messages. MANUAL: In this manual mode, the consumer doesn’t send an acknowledgment for the messages it processes. And we’re using Spring Kafka to send messages from our application to the Kafka server. Dependencies. g. I am using Confluent. To create messages, we first need to configure a ProducerFactory. Does MessageListenerContainer mean consumer? Jan 9, 2024 · spring. receiveData(@Payload String student ) {. This is known as the Idempotent Receiver pattern and Spring Integration provides an implementation of it. Applications that need to read data from Kafka use a KafkaConsumer to subscribe to Kafka topics and receive messages from these topics. 0 the zookeeper server is deprecated and and it is using bootstrap-server, and it will take broker ip address and port. Try consuming using the kafka-console-consumer with --from-beginning flag. because that data has been deleted): Aug 25, 2020 · I'm new to Python. When it restarts on its own, i found in the logs the following trace: Factories drive a lot of functionality in Spring Boot. 1. ”. id. I can't get the consumer code to work, it does not get invoked when a new message appears in Apr 20, 2023 · However, my consumer code does not seem to be receiving any messages from the Kafka topic. Producer publish message to Kafka, but Consumer not receive any message. kafkaTemplate. Try changing your group. Multithreading is “the ability of a central processing unit (CPU) (or a single core in a multi-core processor) to provide multiple threads of execution concurrently, supported by the operating system. X:9092 —listings-incoming —from-beginning —consumer-property group. That's why your Consumer code couldn't consume with the same group. foreach(((key, value) -> {. As you can see from the logs, it was able to connect to the topic. The producer will start and wait for you to enter input. resetOffsets=true spring. The topics property is set to the value of the kafka. listener Apr 19, 2018 · 3. Or if using the string deserailizer, you have a String of JSON and you must parse it manually. You can simply print the messages received: @ComponentclassConsumer{@KafkaListener(topics={"hobbit"}, groupId="spring-boot-kafka")publicvoidconsume(String quote){System. RECORD is not supported when you use this interface, since the listener is given the complete batch. Previously, the container threads looped within the consumer. Of course, we’ll need to add the standard spring-kafka dependency to our pom. out. xx:6667:false for producing. Consumer class. The receive() method is called whenever a message is received on the specified topic. Mar 10, 2022 · The kafka listener is not being able to consume messages unless written in a different way. This header is used on the inbound side to provide appropriate conversion of each header value to the original type. We are able to consume all the messages posted in the topic. When I ran "kafka-console-consumer --bootstrap-servers --topic ", I could see every message that was being received as soon as it got published ( as seen on the consumer console) But the python script is not able to receive the messages in the same way. public ConsumerFactory<String, Object> consumerFactory() {. 5: Use this interface for processing all ConsumerRecord instances received from the Kafka consumer poll() operation when using auto-commit or one of the container-managed commit methods. auto-offset-reset}") private String offset; here you can see all consumer configs. First, we’ll add the spring-kafka-test artifact: And finally we’ll add the Testcontainers Kafka dependency, which is also available over on Maven Central: Feb 9, 2012 · 3. /bin/kafka-console-producer. poll() method waiting for the topic to appear while logging many messages. You will also find links to other related articles on Spring Boot and Kafka integration. reset = earliest. – Jun 29, 2015 · 1. Lets say that the message is send by the key which is myKey. For now I want to have a consumer and a producer. size” needs to be updated first. net 1. To do this, you can use the following command: kafka-consumer-groups –describe –group. getLogger Jun 17, 2022 · If you are actually operating within a web request and still receive this message, your code is probably running outside of DispatcherServlet: In this case, use RequestContextListener or RequestContextFilter to expose the current request. This guarantees sequential message appending within that partition. There are 2 Spring Boot microservices (account-service & user-service) with Java. println("received= "+ quote Aug 30, 2020 · I have a spring boot app with single kafka consumer to get messages from some topic. receive(config. Use the poll method to poll message Creating Consumer Sep 2, 2013 · I am building a Apache Kafka consumer to subscribe to another already running Kafka. readTree(student); // for example, but should extract ObjectMapper to a field. if it is not possible using consumer client itself, kafka-consumer-groups. Chapter 4. It works if I'm not using spring-kafka, just pure kafka-api. I'm using spring-kafka 2. Kafka Consumers: Reading Data from Kafka. Feb 18, 2020 · I'm working on a simple application using spring boot and Kafka to save an object to a Kafka topic and then there is a consumer that will listen and add that record to a in memory database. id, add to your Consumer : Spring Messaging Message Conversion. 2. code: Dec 20, 2019 · I initially thought it was because of the producer which was publishing in batch. Start the application using the included Maven wrapper. A consumerFactory is required. Feb 17, 2019 · I am seeing spring Kafka code and I have some doubts: If we are using 1 @kafkaListener with 2 topics then spring Kafka creates a single MessageListenerContainer. Your other options are to use distinct groups or to call two different processing methods but use one group. I saw in other answers to make sure that AUTO_OFFSET_RESET_CONFIG is set to "earliest" and that the GROUP_ID_CONFIG is unique which I did, however still the Nov 27, 2016 · In kafka_2. println(message); The properties are in application. Procedure. with different logic for every type of message. Jan 10, 2024 · Overview. Sep 29, 2021 · krb5conf: # Change location to your local location. Scenario: The consumer service is down and during this period some messages are send to it's topic. I am trying to build a simple spring boot Kafka Consumer to consume messages from a kafka topic, however no messages get consumed as the KafkaListener method is not getting triggered. I am trying to consume json object ({"name" : "foo"}) and convert it to CreateResponse class. But I was wrong: the application 2 does not receive the kafka topic if the application 1 is running (and it receives he topic). Jms Factory code: Lifecycle Management. Later when u run the producer the consumer consumes the messages. Apache Kafka is an event streaming platform that collects, processes, stores, and integrates data at scale. Mar 6, 2019 · The resetoffsets and startOffset properties are set as below spring. sh --zookeeper {localhost:port} --topic {topic_name} --from-beginning. Jan 8, 2024 · AckMode. It's probably some problem communicating with the broker; that event was added ( issue here) so applications can be informed that the kafka Consumer is "stuck" in the poll for some reason. I've follow below topic but not work for me. core. Dec 5, 2019 · what value have? @Value("${spring. Listener 1 - Not being able to consume messages if i use type mapping (token:type) that is a standalone producer application a standalone consumer application. getTopic(), 0, 0) It gives me this error: Method threw 'java. Open the project in your IDE of choice. I'm using kafka high level consumer client code in java. X. 0! Receiving Messages You can receive messages by configuring a MessageListenerContainer and providing a message listener or by using the @KafkaListener annotation. ms, you may wish to invoke flush() before waiting or, for convenience, the template has a constructor with an autoFlush parameter that causes the template to flush() on each send. Jul 12, 2016 · Thanks Stepio, I tried with removing StringJsonMessageConverter, but still i don't see messages are consumed. topic()); //TODO. Apr 3, 2018 · same issue here. ms = 101. Using properties, create a kafka consumer 2. Jun 26, 2017 · Run the consumer before running the producer so that the consumer registers with the group coordinator first. Confluent's guides are pretty helpful. You need to use the message-driven-channel-adapter. You learned in Sending Messages to Confluent Cloud with Spring Boot that ProducerFactory instantiates Apache Kafka producers. id=group2 Haven't seen messages showing up but what is showing is: Aug 13, 2022 · In fact, it's recommended to disable that setting. This prevents the container from starting if any of the configured topics are not present on the broker. We have a Java application which consumes Kafka messages, using org. Access to the Consumer object is provided. auto-offset-reset=latest spring. I don't see @SpringBootApplication configuration to be sure that Spring Kafka is auto-configured. Now, let’s set up the Kafka consumer configurations. Producer instances are thread safe. You can receive messages by configuring a MessageListenerContainer and providing a message listener or by using the @KafkaListener annotation. In this tutorial, we’ll learn how to create a Kafka listener and consume messages from a topic using Kafka’s Consumer API. apache. startOffset=latest. Oct 22, 2022 · This way I was sure that both of them will receive the kafka message. The producer sends the encrypted message and we are decrypting the actual message using deserializer. Mar 27, 2015 · 1. 6 Mar 19, 2019 · While producing the values on the topic, only 3 consumers out of 5 are receiving messages, while other 2 consumers are not receiving messages at all. I'm using consumer group running on number of threads equivalent to number of partitions. Complete the following steps to receive messages that are published on a Kafka topic: Create a message flow containing a KafkaConsumer node and an output node. Consumers periodically send heartbeats, telling the broker that they are alive. sh to test your consumer, it consumed data from the topic and changed an offset. Feb 7, 2018 · 0. sh utility can be used For the latest stable version, please use Spring for Apache Kafka 3. location: C:\\Users\\src\\main\\resources\\kafka\\krb5nonprod. Mar 9, 2021 · I have read that configuring Heartbeat or Keep Alive on MQ and the client would help. Now, my problem is that when my producer pushes message to servermy consumer does not receive them . But my consumer part is not working. integration. As soon as the kafka consumer stop consuming messages a cpu leak starts. There are links on that issue to an open Kafka JIRA ticket. For example I send a messages {1,2,3,4,5} to the topic when API is down Start the API and the consumer should consume the messages {1,2,3,4,5} Currently. Sep 16, 2019 · If using a json deserailizer, you have a list, not a single Student. Feb 5, 2016 · Running the command line tools for the consumer for the same topic , I do see messages with the --from-beginning option and it hangs otherwise. Try kafka-console-consumer --topic rahul --bootstrap-server localhost:9092. return input -> input. sh, my consumer only detects and prints avery other message. Sometimes, we may want to delay the processing of messages from Kafka. The consumer service listens to a topic pattern. Ordering Within a Partition and Its Challenges. An example is a customer order processing system designed to process orders after a delay of X seconds, accommodating cancellations within this timeframe. input. i performed a lot of tests and I can say that the application 2 receives the messages from kafka only if the application 1 is off. vf ni su zv kr qi om qz ig hv